1. Field of the Invention
The present invention relates to a dual-dircuit master valve for hydraulically actuated power brakes.
2. Description of the Prior Art
German Unexamined Patent Application DE-OS No. 29 52 035 discloses a hydraulic dual-circuit power brake having a brake valve which has two ram-actuated individual valves. The rams are in functional connection with each other via an equalization lever. The equalization lever serves to assure a uniform build-up of pressure in both brake circuits.
Also, German Unexamined Patent Application DE-OS No. 29 41 781 discloses a main brake cylinder for a hydraulically actuatable dual-circuit vehicle brake system whose actuating rams are actuated via an equalizing device which is formed as a balance beam. The balance beam serves to produce the same hydraulic pressure in both brake circuits despite unavoidable irregularities resulting from materials and construction.
The equalizing devices which are formed as balance beams have a complicated construction, including balance beams, springs and counterpieces. In addition, when one brake circuit fails, dependable operation of the remaining brake circuit is not assured without additional expensive countermeasures.